So, you are looking to lose some weight... and your main concern is your abdominal area. If that was flatter and firmer, you could accept the little extra around your hips and on your arms, right? I am sure you have all heard of "spot reduction", the idea is to work muscles in a certain area of your body and burn the fat off from there and there alone. There are ads out there for endless products that offer this as well... even if they do not use the term "spot reduction".
The problem is, this is not how our body works. We can not burn off abdominal fat by doing crunches any more than we can decide where to deposit the fat cells when we eat those extra treats. Our body burns fat for fuel (along with carbs and protein), so with the proper plan, you can burn fat from your body. You can not decide which part of your body the fat will be burned from, that comes down to where it is stored, how much is stored, if you are burning calories through diet and / or exercise and your body type. If fat tends to go to your abdominals first, it will most likely be burned from there last.
The most important thing to remember that no diet and no exercise alone will help you lose weight. You need to make sure you are eating a balanced diet and doing the proper exercises to burn fat. You need to keep your metabolism going strong and build muscle in order to lose the weight and keep it off. If you did not gain the weight over night, chances are, you will not lose it over night either. Be realistic with your goals and get help when you need it. Even personal trainers hire personal trainers... we all need some help sometimes!